1 /* 2 * Copyright (c) 1990, 1991, 1993, 1994, 1995, 1996, 1997 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that: (1) source code distributions 7 * retain the above copyright notice and this paragraph in its entirety, (2) 8 * distributions including binary code include the above copyright notice and 9 * this paragraph in its entirety in the documentation or other materials 10 * provided with the distribution, and (3) all advertising materials mentioning 11 * features or use of this software display the following acknowledgement: 12 * ``This product includes software developed by the University of California, 13 * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of 14 * the University nor the names of its contributors may be used to endorse 15 * or promote products derived from this software without specific prior 16 * written permission. 17 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED 18 * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF 19 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. 20 */ 21 22 /* \summary: Cisco HDLC printer */ 23 24 #ifdef HAVE_CONFIG_H 25 #include <config.h> 26 #endif 27 28 #include "netdissect-stdinc.h" 29 30 #include "netdissect.h" 31 #include "addrtoname.h" 32 #include "ethertype.h" 33 #include "extract.h" 34 #include "chdlc.h" 35 #include "nlpid.h" 36 37 static void chdlc_slarp_print(netdissect_options *, const u_char *, u_int); 38 39 static const struct tok chdlc_cast_values[] = { 40 { CHDLC_UNICAST, "unicast" }, 41 { CHDLC_BCAST, "bcast" }, 42 { 0, NULL} 43 }; 44 45 46 /* Standard CHDLC printer */ 47 void 48 chdlc_if_print(netdissect_options *ndo, const struct pcap_pkthdr *h, const u_char *p) 49 { 50 ndo->ndo_protocol = "chdlc"; 51 ndo->ndo_ll_hdr_len += chdlc_print(ndo, p, h->len); 52 } 53 54 u_int 55 chdlc_print(netdissect_options *ndo, const u_char *p, u_int length) 56 { 57 u_int proto; 58 const u_char *bp = p; 59 60 ndo->ndo_protocol = "chdlc"; 61 if (length < CHDLC_HDRLEN) 62 goto trunc; 63 proto = GET_BE_U_2(p + 2); 64 if (ndo->ndo_eflag) { 65 ND_PRINT("%s, ethertype %s (0x%04x), length %u: ", 66 tok2str(chdlc_cast_values, "0x%02x", GET_U_1(p)), 67 tok2str(ethertype_values, "Unknown", proto), 68 proto, 69 length); 70 } 71 72 length -= CHDLC_HDRLEN; 73 p += CHDLC_HDRLEN; 74 75 switch (proto) { 76 case ETHERTYPE_IP: 77 ip_print(ndo, p, length); 78 break; 79 case ETHERTYPE_IPV6: 80 ip6_print(ndo, p, length); 81 break; 82 case CHDLC_TYPE_SLARP: 83 chdlc_slarp_print(ndo, p, length); 84 break; 85 case ETHERTYPE_MPLS: 86 case ETHERTYPE_MPLS_MULTI: 87 mpls_print(ndo, p, length); 88 break; 89 case ETHERTYPE_ISO: 90 /* is the fudge byte set ? lets verify by spotting ISO headers */ 91 if (length < 2) 92 goto trunc; 93 if (GET_U_1(p + 1) == NLPID_CLNP || 94 GET_U_1(p + 1) == NLPID_ESIS || 95 GET_U_1(p + 1) == NLPID_ISIS) 96 isoclns_print(ndo, p + 1, length - 1); 97 else 98 isoclns_print(ndo, p, length); 99 break; 100 default: 101 if (!ndo->ndo_eflag) 102 ND_PRINT("unknown CHDLC protocol (0x%04x)", proto); 103 break; 104 } 105 106 return (CHDLC_HDRLEN); 107 108 trunc: 109 nd_print_trunc(ndo); 110 return (ND_BYTES_AVAILABLE_AFTER(bp)); 111 } 112 113 /* 114 * The fixed-length portion of a SLARP packet. 115 */ 116 struct cisco_slarp { 117 nd_uint32_t code; 118 #define SLARP_REQUEST 0 119 #define SLARP_REPLY 1 120 #define SLARP_KEEPALIVE 2 121 union { 122 struct { 123 uint8_t addr[4]; 124 uint8_t mask[4]; 125 } addr; 126 struct { 127 nd_uint32_t myseq; 128 nd_uint32_t yourseq; 129 nd_uint16_t rel; 130 } keep; 131 } un; 132 }; 133 134 #define SLARP_MIN_LEN 14 135 #define SLARP_MAX_LEN 18 136 137 static void 138 chdlc_slarp_print(netdissect_options *ndo, const u_char *cp, u_int length) 139 { 140 const struct cisco_slarp *slarp; 141 u_int sec,min,hrs,days; 142 143 ndo->ndo_protocol = "chdlc_slarp"; 144 ND_PRINT("SLARP (length: %u), ",length); 145 if (length < SLARP_MIN_LEN) 146 goto trunc; 147 148 slarp = (const struct cisco_slarp *)cp; 149 ND_TCHECK_LEN(slarp, SLARP_MIN_LEN); 150 switch (GET_BE_U_4(slarp->code)) { 151 case SLARP_REQUEST: 152 ND_PRINT("request"); 153 /* 154 * At least according to William "Chops" Westfield's 155 * message in 156 * 157 * https://web.archive.org/web/20190725151313/www.nethelp.no/net/cisco-hdlc.txt 158 * 159 * the address and mask aren't used in requests - 160 * they're just zero. 161 */ 162 break; 163 case SLARP_REPLY: 164 ND_PRINT("reply %s/%s", 165 GET_IPADDR_STRING(slarp->un.addr.addr), 166 GET_IPADDR_STRING(slarp->un.addr.mask)); 167 break; 168 case SLARP_KEEPALIVE: 169 ND_PRINT("keepalive: mineseen=0x%08x, yourseen=0x%08x, reliability=0x%04x", 170 GET_BE_U_4(slarp->un.keep.myseq), 171 GET_BE_U_4(slarp->un.keep.yourseq), 172 GET_BE_U_2(slarp->un.keep.rel)); 173 174 if (length >= SLARP_MAX_LEN) { /* uptime-stamp is optional */ 175 cp += SLARP_MIN_LEN; 176 sec = GET_BE_U_4(cp) / 1000; 177 min = sec / 60; sec -= min * 60; 178 hrs = min / 60; min -= hrs * 60; 179 days = hrs / 24; hrs -= days * 24; 180 ND_PRINT(", link uptime=%ud%uh%um%us",days,hrs,min,sec); 181 } 182 break; 183 default: 184 ND_PRINT("0x%02x unknown", GET_BE_U_4(slarp->code)); 185 if (ndo->ndo_vflag <= 1) 186 print_unknown_data(ndo,cp+4,"\n\t",length-4); 187 break; 188 } 189 190 if (SLARP_MAX_LEN < length && ndo->ndo_vflag) 191 ND_PRINT(", (trailing junk: %u bytes)", length - SLARP_MAX_LEN); 192 if (ndo->ndo_vflag > 1) 193 print_unknown_data(ndo,cp+4,"\n\t",length-4); 194 return; 195 196 trunc: 197 nd_print_trunc(ndo); 198 } 199